David hall rice



(No Model.)

11. H. RICE. ELECTRIC CALL BELL. NO. 446,712. Patented. Feb. 17,1891.

Fins/X UNiTsn STATES PATENT Utmost DAVID HALL RICE, OF LOW'ELIJ, h.IASSAC1lIIISE'l."IS, ASSIGNOR TO TIIE CURRIER TELEPHONE BRILL COMPANY, OF MASSACHUSETTS.

ELECTRlC CALL-BELL.

SPECIFICATION forming part of Letters Patent No. 4 5,712, dated February 17, 1891.

Application filed November 16, 1881. Serial No, 45,956. (No model.)

To (all whom it may concern:

Be it known that I, DAVID IIALL RICE, of Lowell, in the county of Middlesex and State of Massachusetts, have invented a new and useful Improvement in Electric Call-Bells, of which the following is a specification.

My invention relates to the electric call-bell invented by Jacob B. Currier and shown in his patent, No. 246,374, dated August 30, 1881; and it consists in applying to said Currier bell an automatic circuit breaking device working in the time of the vibration of the hammer of the bell, and so adjusted as only to be set in action when the bell-hammer has reached its amplitude of vibration, whereby I am enabled, after the bell has once been set to ringing by the calling device, to make it ring itself indefinitely without reference to the caller until it is stopped by breaking the circuit elsewhere, as hereinafter described.

In the drawings, Figure 1. shows a part of a circuit with the caller at the calling-station and one of the subscribers stations having a Uurrier bell provided with my improvement. Fig. 2 shows a modification of my invention.

A is the Currier calling device at the central office, which is so well known as not to require an elaborate description. Its circuitbreaker a is held away from contact with its tangent-point b by the lever 0; but when the lever is withdrawn in the usual manner to permit the circuit-breaker to vibrate it will form an electrical contact with the tangentpoint I), not only intermittentlywhile vibrating, but also constant when at rest and until pushed aside by the lever 0 again.

B is the battery.

G is the ground-connection, and the circuit is also grounded at the other end beyond the farthest subscribers station in the usual manner,

G is the Currier bell at a subscribers station. II is itshaminer, and M is its magnet, all arranged in the usual manner, so that the bell shall be rung by a vibrating or intermittent current through the bell-magnet synchronous with the movements of the hammer. ll'hen such a current is sent by the circuit-breaker a over the line L, the hammer II constantly increases the amplitude of its vibrations until it reaches and strikes the bell 0. Just within reach of the longer vibrations of the hammer I place a long slender spring S,fixed in a post p and resting in electrical contact with the point of a metal block P when at rest, as shown, but capable of being lifted from the block when struck by the hammer II, so as to break the contact. carried from the callingstation to the block P. Thence the electric current passes through the spring S and its post 1). From thence the line is continued to the magnet, and from the latter continues on to the next station.

The mechanism operates as follows: The circuit-breaker is set to the required length to produce an intermittent current synchronous with the hammer II, and is set in vibration, sending the current over the line and through the magnet llI, thus causing the hammer to reach and strike its bell. \Vhen it rebounds from the bell and is drawn toward the magnet, it reaches and strikes the spring S, thus breaking the current at P, and it continues to do so at each vibration, and thus forms a broken current in its own time, which continues to ring the bell after the circuitbreaker a has ceased to vibrate and until the circuit is broken by the lever 0 being brought against the circuit-breaker and removing it from its confact-point b.

The advantage of my improvement is that the bell can be sounded for an indefinite time by once setting the caller in 1notion,which is of great advantage. For instance, suppose the hammer II vibrates about fourteen hundred times perminute. The eircuit-breakera will have to be shortened so much that it will sound the bell ordinarily but a few seconds with once Withdrawing the lever 0, while with my improvement when the bell once commences to sound it will continue to do so until stopped.

It is obvious that ditferent forms of arrangement of the spring S and block P may be adopted, or that a lever pivoted at p may be used in place of the spring S without departing from the spirit of myinvention, the novel feature of which consists in applying to this kind of a bell an automatic mechanism oper ated in the time of the hammer, after the latter has been set in motion by a vibrative or broken current, to produce an intermittent The line L is current through the magnet. The spring i. may, instead of causing the current to cease flowing through the magnet, be made to shortcircuit it around the magnet, and thus pro-' duce a broken or uudulatory current through the latter, as shown in Fig. 2. In this case the line L is carried directly to the spring S, and when the hammer II touches the spring it flows through the hammer II and the line L to the main circuit L, or it may be sent directly to the ground instead of onto the main line again. Contact-points of platinum are applied to the hammer and spring.

hat I claim as new and of my invention 

